DeSousa, a New York City native who moved to Baltimore in 1983 and went to Morgan State University, will assume responsibility for the department immediately, the mayor said. Following appropriate approvals, his appointment as commissioner will be made permanent.

"As I have made clear, reducing violence and restoring the confidence of our citizens in their police officers is my highest priority," Pugh said. "The fact is, we are not achieving the pace of progress that our residents have every right to expect in the weeks since we ended what was nearly a record year for homicides in the City of Baltimore."

The city ended 2017 with 343 killings, making the homicide rate about 56 killings per 100,000 people, a per-capita record.

Baltimore Police Department Commissioner Kevin Davis listens to a question during a press conference at City Hall highlighting a Justice Department investigation into the Baltimore City Police Department Aug. 10, 2016, in Baltimore, Maryland.

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DeSousa said he was honored to be tapped as the city's next top cop.

"Baltimore has long been my home and I've spent my career on its streets and in its neighborhoods to address problems and bring about solutions that are meaningful for the people we serve," DeSousa said. "I am committed to this important work more than ever and look forward to validating the trust of Mayor Pugh, my fellow officers and most importantly, the citizens of Baltimore each and every day."

DeSousa deferred completion of his degree at Morgan State in order to join the Baltimore Police Department in 1988 but eventually received his degree in applied liberal arts in 1997.